The year 2009 is likely to rank in the top 10 warmest on record since the beginning of instrumental climate records in 1850, according to data sources compiled by the World Meteorological Organization (WMO). The global combined sea surface and land surface air temperature for 2009 (January–October) is currently estimated at 0.44°C ± 0.11°C (0.79°F ± 0.20°F) above the 1961–1990 annual average of 14.00°C/57.2°F. The current nominal ranking of 2009, which does not account for uncertainties in the annual averages, places it as the fifth-warmest year. The decade of the 2000s (2000–2009) was warmer than the decade spanning the 1990s (1990–1999), which in turn was warmer than the 1980s (1980–1989). More complete data for the remainder of the year 2009 will be analyzed at the beginning of 2010 to update the current assessment. 
This year above-normal temperatures were recorded in most parts of the continents. Only North America (United States and Canada) experienced conditions that were cooler than average. Given the current figures, large parts of southern Asia and central Africa are likely to have the warmest year on record.
Climate extremes, including devastating floods, severe droughts, snowstorms, heat waves and cold waves, were recorded in many parts of the world. This year the extreme warm events were more frequent and intense in southern South America, Australia and southern Asia, in particular. La Niña conditions shifted into a warm-phase El Niño-Southern Oscillation (ENSO) in June. The Arctic sea ice extent during the melt season ranked the third lowest, after the lowest and second-lowest records set in 2007 and 2008, respectively.
Regional temperature anomalies
The year 2009 (January–October) was again warmer than the 1961–1990 average all over Europe and the Middle East. The year started with a mild January in northern Europe and large parts of Asia, while western and central Europe was colder than normal. The European summer was also warmer than the long-term average, particularly over the southern regions. A heat wave at the beginning of July affected the United Kingdom, France, Belgium and Germany, and some stations in Norway experienced new maximum temperature records.
India had an extreme heat wave event during May, which caused 150 deaths. A heat wave hit northern China during June, with daily maximum temperatures above 40°C; historical maximum temperature records were broken for the summer in some locations.
The austral autumn (March to May) was extremely warm in Argentina, Uruguay, Paraguay and southern Brazil. With daily temperatures ranging from 30°C to 40°C, several records were broken during this season.
So far, Australia has had the third-warmest year on record. The year 2009 was marked by three exceptional heat waves, which affected south-eastern Australia in January/February and November, and subtropical eastern Australia in August. The January/February heat wave was associated with disastrous bushfires that caused more than 173 fatalities.
Severe droughts
China suffered its worst drought in five decades. Water levels in parts of the Gan River and Xiangjiang River were the lowest in the past 50 years. In India the poor monsoon season caused severe drought impacts in 40 per cent of the districts. The north-western and north-eastern parts of the country were badly affected. It was reported to be one of the weakest monsoon seasons since 1972.
In North America, Mexico experienced severe-to-exceptional drought conditions by the month of September. In the United States, the western region was the most affected by a moderate-to-exceptional drought by the end of October. Nevertheless, the total area affected by drought in the United States during October was the second-smallest value recorded in this decade.
Drought in Central Argentina caused severe damage to agriculture, livestock and water resources. The situation was most severe at the end of October, with very high temperatures reported as well.
Over the key agricultural areas of the Murray-Darling Basin and the south-western part of Western Australia, rainfall was generally below normal. The passage of another year without any sustained above-normal rainfall has seen long-term rainfall deficits continuing in south-eastern Australia. Sustained dry conditions in the Murray-Darling Basin have now continued for nine years.
End of La Niña and Development of El Niño
La Niña-like conditions were present in early 2009, followed by the development of El Niño patterns starting in June 2009. During June–September 2009, sea surface temperatures were generally about 1°C warmer than the long-term average across the central and eastern equatorial Pacific. An El Niño event is currently underway, with the early phase of the event holding steady at weak-to-moderate levels through July–September. During October, almost all indicators of El Niño became noticeably stronger.
Tropical cyclone season
The 2009 Atlantic hurricane season closed with the fewest named storms and hurricanes since 1997, most likely due to the unfavorable cyclonic conditions caused in part by El Niño. A total of nine named tropical storms were formed, including three hurricanes, two of which were major hurricanes at Category 3 strength or higher.
In the East Pacific, 20 named tropical storms were recorded, eight of which evolved into hurricanes and five of which became major hurricanes.
In the western North Pacific, 22 named tropical storms have been recorded so far, and 13 of them reached the intensity of typhoon, compared to the long-term averages of 27 and 14, respectively.
The Australian and South Indian Ocean cyclone seasons recorded near-average activity. In the Australian region, there were 10 systems during this season, with Hamish the most significant one, although it did not make landfall. It reached category 5 intensity and was the most intense cyclone observed off the eastern Queensland coast since 1918.
Third-lowest Arctic sea ice
According to scientific measurements, Arctic sea ice has declined dramatically over the past 30 years at least, with the most extreme decline seen in the summer melt season. Arctic sea ice extent during the 2009 melt season was 5.10 million km2, which is the third-lowest on record after the 2007 record (4.3 million km2) and 2008 (4.67 million km2), since satellite measurements began in 1979.WMO
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